From 44d494417278e49f5b42bd3ded1801b6d2254db8 Mon Sep 17 00:00:00 2001
From: Keith Packard <keithp@keithp.com>
Date: Tue, 14 Oct 2008 17:18:45 -0700
Subject: [PATCH] agp/intel: Reduce extraneous PCI posting reads during init
Instead of doing a posting read after each GTT entry update, do a single one
at the end of the writes. This should reduce boot time a tiny amount by
avoiding a lot of extra uncached reads.
Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
---
drivers/char/agp/intel-agp.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/char/agp/intel-agp.c b/drivers/char/agp/intel-agp.c
index f1fe7490131..81f09424447 100644
--- a/drivers/char/agp/intel-agp.c
+++ b/drivers/char/agp/intel-agp.c
@@ -214,8 +214,8 @@ static int intel_i810_configure(void)
if (agp_bridge->driver->needs_scratch_page) {
for (i = 0; i < current_size->num_entries; i++) {
writel(agp_bridge->scratch_page, intel_private.registers+I810_PTE_BASE+(i*4));
- readl(intel_private.registers+I810_PTE_BASE+(i*4)); /* PCI posting. */
}
+ readl(intel_private.registers+I810_PTE_BASE+((i-1)*4)); /* PCI posting. */
}
global_cache_flush();
return 0;
@@ -775,8 +775,8 @@ static int intel_i830_configure(void)
if (agp_bridge->driver->needs_scratch_page) {
for (i = intel_private.gtt_entries; i < current_size->num_entries; i++) {
writel(agp_bridge->scratch_page, intel_private.registers+I810_PTE_BASE+(i*4));
- readl(intel_private.registers+I810_PTE_BASE+(i*4)); /* PCI Posting. */
}
+ readl(intel_private.registers+I810_PTE_BASE+((i-1)*4)); /* PCI Posting. */
}
global_cache_flush();
@@ -991,8 +991,8 @@ static int intel_i915_configure(void)
if (agp_bridge->driver->needs_scratch_page) {
for (i = intel_private.gtt_entries; i < current_size->num_entries; i++) {
writel(agp_bridge->scratch_page, intel_private.gtt+i);
- readl(intel_private.gtt+i); /* PCI Posting. */
}
+ readl(intel_private.gtt+i-1); /* PCI Posting. */
}
global_cache_flush();
--
2.41.3